{"cik":2114521,"taxonomy":"us-gaap","tag":"RetainedEarningsAccumulatedDeficit","label":"Retained Earnings (Accumulated Deficit)","description":"The cumulative amount of the reporting entity's undistributed earnings or deficit.","entityName":"CSB Financial Inc.","units":{"USD":[{"end":"2025-12-31","val":15896832,"accn":"0001104659-26-078754","fy":2026,"fp":"Q1","form":"10-Q","filed":"2026-06-29"},{"end":"2025-12-31","val":15896832,"accn":"0001104659-26-094726","fy":2026,"fp":"Q2","form":"10-Q","filed":"2026-08-12","frame":"CY2025Q4I"},{"end":"2026-03-31","val":15983563,"accn":"0001104659-26-078754","fy":2026,"fp":"Q1","form":"10-Q","filed":"2026-06-29","frame":"CY2026Q1I"},{"end":"2026-06-30","val":16152717,"accn":"0001104659-26-094726","fy":2026,"fp":"Q2","form":"10-Q","filed":"2026-08-12","frame":"CY2026Q2I"}]}}